My dog needs a prong collar to walk nice on a leash, but I can't get it fitted correctly. Would a collar with smaller links fit better?

My 10 month old dobie needs a prong collar to walk nice on a leash. Nothing else works. My problem is I was putting it too loose and he now has bumps on the front of his neck down low where the collar should not be. After finding tour website and reading how to fit a prong collar I removed a link and set it up behind his ears over his and now it just seems too tight. The skin looks pinched and he gulps at times. Would a collar with smaller links fit better? This is my fifth doberman and I never had this problem before because the others responded to the correction even though the collar was too low. But this boy ignores the correction.I really need to fit this right for him.

Thank you,
Carole